使用航空深弹驱赶潜艇建模与仿真

非战争时期,驱赶可疑潜艇是航空深弹的主要作战任务,也是其自身特点和优势体现.首先,在分析驱赶潜艇作战原则的基础上,利用航空深弹爆炸威力模型和潜艇壳体抗冲击模型,给出了深弹起爆时距离目标的安全半径和最大有效半径;然后,根据投弹散布模型和目标定位模型,提出了驱赶潜艇目标的投弹瞄准点位置,通过权衡完成驱赶目标任务概率和对目标潜艇造成毁伤的概率,确定投弹瞄准点.最后,针对声纳系统和磁探仪的不同目标定位条件,仿真分析了具体算例.仿真结果表明,较高的投弹精度和水下目标定位精度能更好地控制作战效果.     

针对容性压电负载的桥式功率放大电路的设计

功率放大电路负责驱动容性压电负载,是整个压电执行器的关键部件.根据某驱动电源中的功率放大电路作为设计对象,通过采用桥式电路结构,从而提高了整体性能;通过研究放大器的共模输入电压范围,从而设定了非对称电源;通过分析波形,从而设定了电压增益;通过采用过压保护和限制电流,增强了电路的安全性;通过计算热工,设置了散热方式;通过使用方波测试法,测定了电路的稳定性.实验结果显示,该方法能实现双极性输出,以至于性能上的提高胜过了成本和复杂性的增加.     

半挂式车辆自主驾驶的轨迹跟踪控制研究

该文针对半挂式车辆的自主驾驶,设计一种基于迭代线性二次型调节器(iLQR)的轨迹跟踪控制器.通过深入研究转向过程中半挂式车辆的运动,建立满足非完整性约束的非线性车辆运动学模型,并根据期望轨迹对其进行线性化,得到线性的轨迹跟踪误差模型.基于扩展卡尔曼滤波器设计车辆状态观测器,估计车辆的航向角.通过对期望轨迹进行基于三次B...     

红外焦平面器件脉冲驱动电路的小型化设计

代表着红外器件发展的主流方向的红外焦平面器件,其正常工作时需要驱动脉冲信号多达十几路,为了使红外焦平面阵列处于最佳工作状态,就必须设计出相应的驱动电路.提出了一种红外焦平面器件驱动电路的设计方法.该电路具有体积小、功耗低及灵活性好等特点,为驱动电路以及成像系统的小型化提供了良好的技术基础.     

嵌入路网图模型的自动驾驶场景描述语言

深度学习的快速发展带动着自动驾驶技术的迅速进步.深度学习感知模型在识别准确率逐步提升的同时,也存在鲁棒性和可靠性不足等隐患,需要在大量场景下进行充分测试以确保达到可接受的安全标准.基于场景的仿真测试是自动驾驶技术的核心和关键,如何描述和生成多样化仿真测试场景是需要解决的关键问题之一.场景描述语言能够描述自动驾驶场景并在虚拟环境中实例化场景获取仿真数据,但现有的场景描述语言大都缺少对于场景道路结构的高层抽象和描述.提出路网属性图来表示路网中抽象出的实体及他们的关系,并设计能简洁描述场景路网结构的语言SceneRoad. SceneRoad可以基于描述的场景道路结构特征构建路网特征查询图.这样,在路网中搜索符合描述的场景道路特征的问题被抽象为路网图上的子图匹配问题,该问题可用VF2算法求解.进一步地,将SceneRoad作为扩展集成到Scenic场景描述语言中.使用拓展后的语言随机生成大量多样的静态场景并构建仿真数据集.仿真数据集的统计信息表明生成的场景具有丰富的场景多样性.不同感知模型在真实和仿真数据集上的训练测试结果表明,模型在两个数据集上的表现呈正相关,意味着模型在仿真数据集上的评估...     

新型混合型限流断路器分析及试验

研究了一种基于高速斥力开关的交直流两用混合型限流断路器方案,该限流断路器在限流过程中先经过一个强迫换流过程,使得触头分离时高速斥力开关上电流减小到较小值,触头分离后再经历一个自然零电压换流过程,将斥力开关电流换流到二极管支路上.重点对限流断路器换流过程进行了理论分析及仿真,分析了其可能出现的4种分断情况.研制了400V/500A限流断路器样机,并进行了不同短路电流上升率的限流试验,验证了理论分析的正确性.     

G伺服在光纤筛选设备中的应用

文章探讨了新型G系列伺服系统的特点,其在光纤筛选设备上的应用;光纤筛选设备的控制原理,在光纤生产环节中的作用,发挥G系列伺服优异性能,提升筛选速度提高设备的利用效率.     

市政养护施工围栏对安全驾驶的实验研究

目的:近几年随着社会经济的发展,市政养护作业增加,而市政养护部门缺少相关的规范和标准,这造成了养护工作无法有效地正常进行。本研究试图从道路使用者对福州市市政维护的满意程度以及整体状况展开实验调查,为中国的道路养护维修提供有效的客观数据。方法:本研究招募私家车,出租车和公交车司机对市政养护的实际驾驶情景中遇到围栏做出减速、变道的反应时,对围栏的总体满意度以及围栏是否影响驾驶行为等方面进行研究,采用E-prime软件采集数据,结果:发现私家车在遇到施工围栏的减速和变道反应快于出租车和公交车;所有车型司机对于施工作业围栏的满意度只有57%;公交车司机的危险性失误行为低于另外两个车型司机。结论:市政养护施工作业对不同道路使用者的安全驾驶行为产生一定影响。     

Effect of cycle time and duty cycle on psychophysically determined acceptable levels in a highly repetitive task

Psychophysical methodology has been used to develop guidelines for lifting and more recently similar methods have been applied to repetitive upper limb movements. While a range of cycle times are usually used, there is often no control for duty cycle. The purpose of this paper is to present psychophysically determined acceptable torques for a common upper limb task, with both cycle time and duty cycle conditions set by the researcher. Eight female participants, sitting at adjustable workstations, performed a simulated in-line screw running task. A computer-controlled torque motor applied a torque every 3, 6, 12 or 20?s with a duty cycle of 25, 50 or 83%. The participants worked with one set of conditions each day and self-selected the highest torque that they felt was acceptable without developing undue pain and discomfort. Duty cycle was found to significantly affect the amount of torque selected. With duty cycle controlled, cycle time was no longer found to have any significant effect on selected torque. Acceptable torques for 25, 50 and 83% duty cycles were 1.09, 0.9 and 0.73 Nm. Discomfort and stiffness were concentrated on the back of the hand and on the thumb web. These findings suggest that increased perception of discomfort with increased frequency (decreased cycle time) may be related to decreased rest/recovery time for muscles.     

After-effects of TFT-LCD display polarity and display colour on the detection of low-contrast objects

Participants performed a word–non-word discrimination task within a car control display emulated on a thin film transistor liquid-crystal display (TFT-LCD). The task simulated an information read-out from a TFT-LCD-based instrument panel. Subsequently, participants performed a low-contrast object detection task that simulated the detection of objects during night-time driving. In experiment 1, words/non-words were presented black-on-white (positive polarity) or white-on-black (negative polarity). In experiments 2 and 3, display colour was additionally manipulated. A positive polarity advantage in the discrimination task was consistently observed. In contrast, positive displays interfered more than negative displays with subsequent detection. The detrimental after-effect of positive polarity displays was strong with white and blue, reduced with amber and absent with red displays. Subjective measures showed a preference for blue over red, but a slight advantage for amber over blue. Implications for TFT-LCD design are derived from the results.

Statement of Relevance: When using TFT-LCDs as car instrument panels, positive polarity red TFT-LCDs are very likely to lead to good instrument readability while at the same time minimising – relative to other colours – the negative effects of an illuminated display on low-contrast object detection during night-time driving.